Dibarboure Gerald

Dibarboure Gerald
Centre National d’Etudes Spatiales | CNES

About

92
Publications
24,824
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,076
Citations
Introduction
Skills and Expertise

Publications

Publications (92)
Preprint
We present a new gridded sea surface height and current dataset produced by combining observations from nadir altimeters and drifting buoys. This product is based on a multiscale & multivariate mapping approach that offers the possibility to improve the physical content of gridded products by combining the data from various platforms and in resolvi...
Article
Swath altimetry is likely to revolutionize our ability to monitor and forecast ocean dynamics. To meet the requirements of the EU Copernicus Marine Service, a constellation of two wide-swath altimeters is envisioned for the long-term (post-2030) evolution of the Copernicus Sentinel 3 topography mission. A series of observing system simulation exper...
Article
Full-text available
This study proposes an approach to estimate the ocean sea surface height signature of coherent internal tides from a 25-year along-track altimetry record, with a single inversion over time, resolving both internal tide contributions and mesoscale eddy variability. The inversion is performed on a reduced-order basis of topography and practically ach...
Article
Full-text available
This paper presents the new global Mesoscale Eddy Trajectory Atlases (META3.1exp DT all-satellites, https://doi.org/10.24400/527896/a01-2021.001, Pegliasco et al., 2021a; and META3.1exp DT two-satellites, https://doi.org/10.24400/527896/a01-2021.002, Pegliasco et al., 2021b), composed of eddy identifications and trajectories produced with altimetri...
Article
Full-text available
We present a new Arctic sea level anomaly dataset based on the combination of three altimeter missions using an optimal interpolation scheme. Measurements from SARAL/AltiKa, CryoSat-2 and Sentinel-3A are blended together, providing an unprecedented resolution for this type of product. Such high-resolution products are necessary to tackle some conte...
Article
Full-text available
The impact of large atmospheric attenuation events on data quality and availability is a critical aspect for future altimetry missions based on Ka-band altimetry. The SARAL/AltiKa mission and its Ka-band nadir altimeter offer a unique opportunity to assess this impact. Previous publications (Tournadre et al., 2009, 2015) already analyzed the impact...
Article
Full-text available
It is essential to monitor accurately current sea level changes to better understand and project future sea level rise (SLR). This is the basis to support the design of adaptation strategies to climate change. Altimeter sea level products are operationally produced and distributed by the E.U. Copernicus services dedicated to the marine environment...
Preprint
Full-text available
Swath altimetry is likely to revolutionize our ability to monitor and forecast ocean dynamics. To meet the requirements of the EU Copernicus Marine Service, a constellation of two wide-swath altimeters is envisioned for the long-term (post-2030) evolution of the Copernicus Sentinel 3 topography mission. A series of Observing System Simulation Exper...
Preprint
The impact of large atmospheric attenuation events on data quality and availability is a critical aspect for future altimetry missions based on Ka-band altimetry. The SARAL/AltiKa mission and its Ka-band nadir altimeter offer a unique opportunity to assess this impact. Previous publications (Tournadre et al. 2009, 2015) already analyzed the impact...
Preprint
Full-text available
This paper presents the new global Mesoscale Eddy Trajectories Atlases (META3.1exp DT all-satellites, https://doi.org/10.24400/527896/a01-2021.001, Pegliasco et al., 2021a and META3.1exp DT two-satellites, https://doi.org/10.24400/527896/a01-2021.002, Pegliasco et al., 2021b), composed of the eddies’ identifications and trajectories produced with a...
Preprint
Full-text available
This study proposes an approach to estimate the Ocean Sea Surface Height signature of coherent internal tidesfrom 25 years of along-track altimetry record, with a single inversion over time, resolving both internal tide contributions andmesoscale eddy variability. The inversion is performed through reduced-order basis with conjugate gradient resolu...
Article
Full-text available
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...
Article
Full-text available
The mean dynamic topography (MDT) is a key reference surface for altimetry. It is needed for the calculation of the ocean absolute dynamic topography, and under the geostrophic approximation, the estimation of surface currents. CNES-CLS mean dynamic topography (MDT) solutions are calculated by merging information from altimeter data, GRACE, and GOC...
Preprint
Full-text available
We present a new Arctic sea level anomaly dataset, based on the combination of three altimeter missions using an optimal interpolation scheme. Measurements from SARAL/AltiKa, CryoSat-2 and Sentinel-3A are blended together providing an unprecedented resolution for this type of products. The final gridded fields cover all latitudes north of 50° N, on a...
Article
Full-text available
Two methods for the mapping of ocean surface currents from satellite measurements of sea level and future current vectors are presented and contrasted. Both methods rely on the linear and Gaussian analysis framework with different levels of covariance definitions. The first method separately maps sea level and currents with single-scale covariance...
Article
Full-text available
The resolutions of current global altimetric gravity models and mean sea surface models are around 12 km wavelength resolving 6km features, and for many years it has been difficult to improve the resolution further in a systematic way. For both Jason 1 and 2, a Geodetic Mission (GM) has been carried out as a part of the Extension-of-Life phase. The...
Preprint
Full-text available
The Mean Dynamic Topography (MDT) is a key reference surface for altimetry. It is needed for the calculation of the ocean absolute dynamic topography, and under the geostrophic approximation, the estimation of surface currents. CNES-CLS Mean Dynamic Topography (MDT) solutions are calculated by merging information from altimeter data, GRACE and GOCE...
Article
The Dynamic Optimal Interpolation (DOI) merges altimetric Sea Surface Height (SSH) data into maps that are continuous in time and space. Unlike the traditional Linear Optimal Interpolation (LOI) method, DOI has the advantage of considering a non-linear temporal propagation of the SSH field. DOI has been successfully applied to along-track pseudo-ob...
Article
Full-text available
The CNES/ISRO altimetric satellite SARAL/AltiKa was launched in February 2013 and since then has provided useful data for various scientific and operational applications in oceanography, hydrology, cryospheric sciences and geodesy. However, a Reaction Wheel problem forced relaxation of the repeatability constraint on the satellite’s orbit, which ha...
Article
Full-text available
For more than 20 years, the multi-satellite Data Unification and Altimeter Combination System (DUACS) has been providing near-real-time (NRT) and delayed-time (DT) altimetry products. DUACS datasets range from along-track measurements to multi-mission sea level anomaly (SLA) and absolute dynamic topography (ADT) maps. The DUACS DT2018 ensemble of p...
Article
Full-text available
The Data Unification and Altimeter Combination System (DUACS) produces sea level global and regional maps that serve oceanographic applications, climate forecasting centers, and geophysics and biology communities. These maps are generated using an optimal interpolation method applied to altimeter observations. They are provided on a global 1∕4∘ × 1...
Article
Full-text available
Global sea surface height wave number spectra are revisited using the most recent, lower-noise satellite altimeter missions from Saral/AltiKa and Sentinel-3 and compared to Jason-2 wave number spectra. Spectral preprocessing is configured to minimize the spectral slope distortion in the mesoscale wavelength range. A geographically variable waveleng...
Article
In this paper we compute a new local mean sea surface (MSS) model along the Sentinel-3A ground track. This so-called hybrid mean profile (HMP) blends the content of an average of 18 months of Sentinel-3A data for wavelengths ranging from 15 to 100 km, and the CNES/CLS 2015 gridded MSS model for larger and shorter scales. The improvement observed on...
Article
Full-text available
The Copernicus Marine Environment Monitoring Service (CMEMS) provides regular and systematic reference information on the physical and biogeochemical ocean and sea-ice state for the global ocean and the European regional seas. CMEMS serves a wide range of users (more than 15,000 users are now registered to the service) and applications. Observation...
Article
Full-text available
The Copernicus Marine Environment Monitoring Service (CMEMS) provides regular and systematic reference information on the physical and biogeochemical ocean and sea-ice state for the global ocean and the European regional seas. CMEMS serves a wide range of users (more than 15,000 users are now registered to the service) and applications. Observation...
Preprint
Full-text available
Global sea surface height (SSH) wavenumber spectra are revisited using the most recent, lower noise satellite altimeter missions from Saral/AltiKa and Sentinel-3, and compared to Jason-2 wavenumber spectra. Spectral pre-processing is configured to minimize the spectral slope distortion in the mesoscale wavelength range. A geographically-variable wa...
Article
Full-text available
The Sea surface Kinematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the poorly known patterns of divergence and their impact on the ocean heat budget, and monitoring of the emerging Arctic up to 82.5 degrees N. SKIM will also make unprecedented di...
Article
Full-text available
The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the unknown patterns of divergence and their impact on the ocean heat budget near the Equator, monitoring of the emerging Arctic up to 82.5°N. SKIM will also make unprecedented di...
Article
Full-text available
For more than twenty years, the multi-satellite DUACS system has been providing Near Real Time (NRT) and Delayed Time (DT) altimetric products. These data are ranging from along-track to multi-mission maps of Sea Level Anomaly (SLA) and Absolute Dynamic Topography (ADT). A reprocessing of 25 years of data, namely: DUACS DT2018, has been carried out...
Article
Full-text available
The DUACS system produces sea level global and regional maps that serve oceanographic applications, climate forecasting centers, geophysics and biology communities. These maps are constructed from optimal interpolation of altimeter observations and are provided on a global 1/4°×1/4° (longitude×latitude) and daily grid resolution framework (1/8°×1/8...
Preprint
Full-text available
This paper is a mini-review contributing to the Oceanobs'19 conference, giving a very short summary and update on the progress of the SKIM mission.
Poster
Full-text available
Recent progress in satellite altimetry 1 has improved the observability of mesoscale structures in the ocean, that govern the energy exchanges in geostrophic oceanic flows 2. Here we analyze the noise levels and observable spatial scales over the global ocean using the wavenumber spectra of the two-year SARAL/Altika (AL) 1Hz and Sentinel-3A (S3A) 1...
Poster
Full-text available
The increase in mesoscale resolution capability of present generation altimeters is expected to further improve our understanding of the contribution of mesoscale processes onto ocean circulation, and to allow for a more reliable assessment of the ability of high-resolution ocean models to resolve these processes. In this context, the recent availa...
Poster
Full-text available
The slope of wavenumber spectra of sea surface height (SSH) over the mesoscale band has been used to infer the processes that govern the energy exchanges in geostrophic oceanic flows 1 , which also involve subsurface ocean dynamics. Observed SSH spectral slopes are generally shallower 2 than the QG theory predictions of k-5 , which has been related...
Article
Full-text available
The French/Indian altimeter project Satellite with ARGOS and AltiKa (SARAL) completed its nominal 3-year mission on the historical European Remote-sensing Satellite (ERS) orbit in Spring 2016. In order to extend the lifetime of the satellite as much as possible, the agencies in charge of SARAL decided to initiate a so-called drifting phase where th...
Article
This paper presents an assessment and comparison of recent mean sea surface (MSS) models. Using a new approach and independent altimeter data sets, we quantify the major improvement of the CNES_CLS15 and the DTU15 models. We observe a reduction in the amplitude of omission errors thanks to the use of new geodetic altimeter data sets (i.e., Cryosat-...
Article
Full-text available
The Sea Surface KInematics Multiscale monitoring (SKIM) mission proposes to use Doppler-based measurements of velocities to provide global estimates of surface currents and ice drift at spatial scales of 40 km and more, with snapshots at least every day for latitudes 75 to 82, and every few days otherwise. Given the contribution of wave motion to D...
Article
Full-text available
We propose a satellite mission that uses a near-nadir Ka-band Doppler radar to measure surface currents, ice drift and ocean waves at spatial scales of 40 km and more, with snapshots at least every day for latitudes 75 to 82°, and every few days for other latitudes. The use of incidence angles of 6 and 12° allows for measurement of the directional...
Conference Paper
Full-text available
The DUACS system produces, as part as the Copernicus Marine Environment and Monitoring Service (CMEMS), high quality multimission altimetry Sea Level products for oceanographic applications, climate forecasting centers, geophysic and biology communities... These products consist in directly usable and easy to manipulate Level 3 (along-track cross-c...
Poster
Full-text available
The slope of wavenumber spectrum of sea surface height (SSH) over the mesoscale band has been used to infer the processes that govern the energy exchanges in geostrophic oceanic flows 1 , which also involve subsurface ocean dynamics. Observed SSH spectral slopes are generally shallower 2 than the QG theory predictions of k-5 , which has been relate...
Article
Full-text available
The India–France SARAL/AltiKa mission is the first Ka-band altimetric mission dedicated primarily to oceanography. The mission objectives were firstly the observation of the oceanic mesoscales but also global and regional sea level monitoring, including the coastal zone, data assimilation, and operational oceanography. SARAL/AltiKa proved also to b...
Article
The future Surface Water Ocean Topography (SWOT) mission aims to observe water bodies and shortscale ocean surface topography with unprecedented spatial resolution and accuracy. However, the topography estimates will be contaminated by errors of various signals (geophysical and instrumental) featuring, in large part, strong dependencies on the rada...
Article
Full-text available
Mapping of surface currents using the Doppler information of radar backscatter is now a mature technique using shore-based radars operating at frequencies between 5 and 50 MHz, and new concepts of satellite missions are emerging. A characteristic that is common to these concepts and HF radars is the measurement of radial velocities unevenly distrib...
Poster
Full-text available
The slope of wavenumber spectrum of sea surface height (SSH) over the mesoscale band has been used to infer the processes that govern the energy exchanges in geostrophic oceanic flows 1 , which also involve subsurface ocean dynamics. Observed SSH spectral slopes are generally shallower 2 than the QG theory predictions of k-5 , which has been relate...
Article
The main oceanographic objective of the future SWOT mission is to better characterize the ocean mesoscale and sub-mesoscale circulation, by observing a finer range of ocean topography dynamics down to 20 km wavelength. Despite the very high spatial resolution of the future satellite, it will not capture the time evolution of the shorter mesoscale s...
Presentation
Full-text available
The better observation of mesoscale and sub-mesoscale oceanic structures is a major challenge of altimetry community in the future years. Indeed, to date, the sea level content provided by most of the conventional altimeters does not allow the observation of ocean scales smaller than 80-100km. (Dibarboure et al., 2014) has shown that this limitatio...
Article
Wavenumber spectra of along-track Sea Surface Height from the most recent satellite radar altimetry missions [Jason-2, Cryosat-2, and SARAL/Altika) are used to determine the size of ocean dynamical features observable with the present altimetry constellation. A global analysis of the along-track 1-D mesoscale resolution capability of the present-da...
Article
Because of the drifting nature of the ground track of Jason-1 during its geodetic mission (GM), there are 1200 overlap events where the Jason-1 GM and Jason-2 tracks align perfectly (less than their altimeter footprint radius) over thousands of kilometers. These overlap events sample homogeneously all longitudes and all time differences (dt) rangin...
Article
Full-text available
The paper gives an overview of the development of satellite oceanography over the past five years focusing on the most relevant issues for operational oceanography. Satellites provide key essential variables to constrain ocean models and/or serve downstream applications. New and improved satellite data sets have been developed and have directly imp...
Article
Altimetry missions are usually presented to the user communities with rather short lifetime durations of the order of 5 years. However in practice, most altimeters can remain in operations for twice as long, although often in a degraded state (coverage and/or accuracy) and with a higher risk of mission loss.Early in the design of the SARAL/AltiKa m...